Total dissolved solids is used to describe the measurement of all substances dissolved in swimming pool water.
What is Total Dissolved Solids (TDS) for pools?
Total dissolved solids, often denoted as TDS, is a combination of all the inorganic and organic matter dissolved in a body of water. Examples include molecular compounds, ionized metals and minerals, or microscopic granular particles free-floating in the water and unable to be filtered. Even with the best filter that can remove most particles from the water, no filter can remove everything, as some particles will always be present in the water.
For swimming pools, total dissolved solids come from debris, contaminates, treatment chemicals added, the local water supply, and the bather load. TDS can be considered how “old” the water in a swimming pool has become, as through evaporation, pure water slowly escapes, but the dissolved solids remain in the water. Different solids in water all have their own saturation points, which if this level is exceeded, any additional solids will come out of solution and either free-float in the water, form precipitate and float to the bottom, or form scale or stains on pool surfaces.
- Wikipedia: “Total Dissolved Solids”, http://en.wikipedia.org/wiki/Total_dissolved_solids
- “Pool & Spa Water Chemistry, A Testing and Treatment Guide, Waterproof Edition, 2005. Taylor”